The analysis of magic-angle spinning nuclear magnetic resonance experiments often includes determining a constant effective replacement for a periodic time-dependent Hamiltonian. We provide a clarifying overview over the two most used approaches, covering their mathematical origin, context, and relationship to each other, as well as their practical use for nuclear magnetic resonance applications. We recommend Floquet theory due to its numerical robustness, efficiency and accuracy.

To characterize the amplitude of dynamic processes in molecules, anisotropic parameters can be measured using solid-state NMR. However, the timescales of motion that lead to such a scaling of the anisotropic interactions are not clear. Using numerical simulations in small spin systems, we could show that mostly the magnitude of the anisotropic interaction determines the range of timescales detected by the scaled anisotropic interaction, and experimental parameters play a very minor role.

Dynamic nuclear polarization requires a waveguide that connects the cold (1–10 K) sample space to the outside. To reduce the heating of the sample, a waveguide is produced from steel which has low thermal conductivity but attenuates the microwaves. Therefore, the inside of the waveguide should be plated with silver to reduce electrical losses. We show a new simple way to electroplate such waveguides with a thin silver layer and show that this improves the experimental performance.

Through the advent of fast magic-angle spinning and high magnetic fields, the spectral resolution of solid-state NMR spectra has recently been greatly improved. To take full advantage of this gain, the magnetic field must be stable over the experiment time of hours or even days. We thus monitor the field by simultaneous acquisition of a frequency reference (SAFR) and use this information to correct multidimensional spectra improving resolution and availability of productive magnet time.